Porous electrode base material, method for manufacturing same, and precursor sheet

Patent metadata

Field	Value
Publication number	US-9716278-B2
Application number	US-201314382723-A
Country	US
Kind code	B2
Filing date	Mar 29, 2013
Priority date	Mar 30, 2012
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

The present invention relates to a method for manufacturing a porous electrode base material including the following steps [1] to [3]: [1] a step for dispersing short carbon fibers (A) to form a sheet-form product; [2] a step for adding, to the sheet-form product, at least one phenolic resin (c) selected from a group consisting of a water soluble phenolic resin and a water dispersible phenolic resin along with carbon powder (d) to form a precursor sheet; and [3] a step for carbonizing the precursor sheet at the temperature of 1000° C. or higher, after the step [2].

First claim

The invention claimed is:

1. A method for manufacturing a porous electrode base material, the method comprising:
[1] dispersing short carbon fibers (A) to form a sheet-form product;
[2] adding, to the sheet-form product, at least one phenolic resin (c) comprising a water soluble phenolic resin and a water dispersible phenolic resin along with carbon powder (d) to form a precursor sheet;
[3] carbonizing the precursor sheet at a temperature of 1000° C. or higher, after said adding [2]; and
[4] after said dispersing [1] and before said adding [2], performing an entanglement treatment of the sheet-form product.

2. The manufacturing method according to claim 1 , further comprising:
[7] after said performing [4] and before said adding [2], performing a first drying treatment of the sheet-form product,
[5] after said adding [2] and before said carbonizing [3], heating and compressing the precursor sheet at a temperature of 100 to 250° C., and
[6] after said adding [2] and before said heating and compressing [5], performing a second drying treatment of the precursor sheet.

3. The manufacturing method according to claim 1 , wherein an average particle diameter of substantial particles or agglomerates of the carbon powder (d) in said adding [2] is 0.1 to 50 μm.

4. The manufacturing method according to claim 1 , further comprising:
[8] after said carbonizing [3], adding a fluorine-based resin dispersion with a solid content of 1 to 30% by mass to the porous electrode base material followed by further drying and performing a heat treatment at 300 to 390° C.

5. A porous electrode base material, comprising:
a sheet-form structure having short carbon fibers (A) bound by a resin carbide (C) derived from a water soluble phenolic resin and a water dispersible phenolic resin,
wherein carbon powder (d) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

6. The porous electrode base material of claim 5 ,
wherein a region having the short carbon fibers (A) and carbon powder (d) bound by the resin carbide (C) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

7. The porous electrode base material of claim 5 ,
wherein a region having the short carbon fibers (A) and carbon powder (d) bound by the resin carbide (C) is included in the vicinity of a surface layer of a single side or both sides of the sheet-form structure,
a pore occupancy in a region X from a surface of a plane having the aforementioned region to a depth of 20 μm is less than 30%, and
a pore occupancy in a region Y from center of the sheet-form structure to a depth of 40 μm in a thickness direction is 50 to 90%.

8. A porous electrode base material, comprising:
a sheet-form structure having short carbon fibers (A) bound by carbon fibers (B) with a fiber diameter of 0.1 to 5 μm and a resin carbide (C) derived from a water soluble phenolic resin and a water dispersible phenolic resin,
wherein the short carbon fibers (A) form a three-dimensional entanglement structure in the sheet-form structure, and
carbon powder (d) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

9. The porous electrode base material of claim 8 ,
wherein
a region having the short carbon fibers (A) and carbon powder (d) bound by the resin carbide (C) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

10. The porous electrode base material of claim 8 ,
wherein
a region having the short carbon fibers (A) and carbon powder (d) bound by the resin carbide (C) is included in the vicinity of a surface layer of a single side or both sides of the sheet-form structure,
a pore occupancy in a region X from a surface of a plane having the aforementioned region to a depth of 20μm is less than 30%, and
a pore occupancy in a region Y from center of the sheet-form structure to a depth of 40 μm in a thickness direction is 50 to 90%.

11. A precursor sheet, comprising:
a sheet-form structure having short carbon fibers (A) bound by at least one phenolic resin (c) comprising a water soluble phenolic resin and a water dispersible phenolic resin,
wherein carbon powder (d) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

12. A precursor sheet, comprising:
a sheet-form structure having short carbon fibers (A) bound by at least one phenolic resin (c) comprising a water soluble phenolic resin and a water dispersible phenolic resin,
wherein a region having the short carbon fibers (A) and carbon powder (d) bound by the phenolic resin (c) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

13. A precursor sheet, comprising:
a sheet-form structure having short carbon fibers (A) bound by at least one phenolic resin (c) comprising a water soluble phenolic resin and a water dispersible phenolic resin,
wherein a region having the short carbon fibers (A) and carbon powder (d) bound by the phenolic resin (c) is included in the vicinity of a surface layer of a single side or both sides of the sheet-form structure,
a pore occupancy in a region X from a surface of a plane having the aforementioned region to a depth of 20 μm is less than 25%, and
a pore occupancy in a region Y from center of the sheet-form structure to a depth of 40 μm in a thickness direction is 35 to 70%.

14. A precursor sheet, comprising:
a sheet-form structure having short carbon fibers (A) and carbon fiber precursor short fibers (b) bound by at least one phenolic resin (c) comprising a water soluble phenolic resin and a water dispersible phenolic resin,
wherein the short carbon fibers (A) form a three-dimensional entanglement structure in the sheet-form structure, and
a region having the short carbon fibers (A) and carbon powder (d) bound by the phenolic resin (c) is localized in the vicinity of a surface layer of a single side or both sides of the sheet-form structure.

15. The method of claim 1 , wherein the sheet-form product, prior to [2] adding the phenolic resin (c), does not comprise a binder.

16. The method of claim 1 , wherein the process does not comprise organic solvent removal from the sheet-form product, prior to [2] adding the phenolic resin (c).

Assignees

• Mitsubishi Chem Corp

Inventors

• Tatsuno Hiroto

Classifications

• C04B2235/604

  Pressing at temperatures other than sintering temperatures · CPC title

• H01M4/8652 Primary

  as mixture · CPC title

• C04B35/63476

  Phenol-formaldehyde condensation polymers · CPC title

• C04B35/83

  Carbon fibres in a carbon matrix · CPC title

• C04B35/63444

  Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI] · CPC title